Mt. Si Bridge over the middle fork of the Snoqualmie river is scheduled for replacement with construction to begin in early 2007.

King County is responsible for almost 200 bridges, but about the only thing these bridges have in common is their owner. The spans come in all shapes, ages, lengths, construction styles, and locations. Managing the health and welfare of the diverse collection of bridges is not easy, so it all begins with regiment of routine inspections.

"We have a huge eclectic mix of bridges of different ages, uses and conditions," said Jim Markus, managing engineer for the King County Road Services Division's Bridge Unit. "What we do is implement a program to keep those bridges safe and operational - whether it's a complex project like replacing the Elliott Bridge; redesigning a sole access bridge like Mt. Si; or a mega project like the South Park Bridge.

"Those three bridges have been on our long-range Capital Improvement Program (CIP) for awhile, but they are very different projects," said Markus. "Yet, the needs for each one was first identified through our bridge inspection program."

All of King County's bridges - from the short timber crossings on a tiny creek to the mighty bridges that span the Duwamish, Cedar and Snoqualmie - are on a routine inspection program. Each bridge is thoroughly examined on a schedule that ranges from 12 to 24 months, and by law no bridge goes longer than two years without an inspection.

In 2004, the Bridge Unit completed 170 inspections. The work began in late spring and stretched into the fall. Now is the time of year that all the data from the inspections is crunched and developed into a work plan for next year.

Information collected from the inspections is used for:

Updating frequency of the bridge's inspection schedule;

Monitoring specific features of the bridge to see if suspected problems are developing;

Requesting maintenance or repairs; and

Determining where a project fits into the CIP, and if it needs to be moved up or down or the priority list.

During the inspections, each bridge is scored from 0-100. Usually the scores don't change that much from year to year because Bridge Unit staff is very aware of each bridge's problems. After the inspection, work orders are written up on a 1-5 priority scale, with 1 being the highest. After this year's round of inspections, there were no Priority 1 projects found. 

"We usually don't find too many surprises since the inspection program ramped up about 10 years ago," said Tim Lane, a supervising engineer in the Bridge Unit. "The inspection program enables us to stay on top of the problems. We don't always have the means to fix them right away, but the county would never keep a bridge open that is unsafe."

Because replacing and rehabilitating bridges is so expensive, and revenues for such projects have dwindled in recent years, the county often does patchwork repairs to keep a bridge operating well beyond its expected lifespan.

Just last weekend, the 91-year-old Elliott Bridge over the Cedar River was closed so county crews could replace badly rusted sections of the bridge deck. A new replacement bridge is under construction adjacent to the old bridge, but it won't be completed until November 2005.

"We're averaging two deck repairs a year on Elliott," said Lane. "The deck is rusting quickly because of the advancing age of the deck. If you look at deck from underside, it looks like a patchwork quilt of metal."

Bridge Unit staff say there are other bridges that are so old or worn out that repairs are only a stop gap until funding becomes available for new bridges. The South Park Bridge over the Duwamish River is on an annual inspection schedule, in addition to a low-tide inspection at the waterline every June and several mechanical/electrical inspections each year to troubleshoot operational problems. Plus, repairs are made every time the railings and supports are damaged by one of the 20,000-plus vehicles that travel over the busy drawbridge each day.

Even out in the rural areas, light traffic takes its toll on the older bridges. The Mt. Si Bridge crosses the Middle Fork of the Snoqualmie River. It provides sole access to only 400 homes, but it is seismically vulnerable, structurally deficient, and functionally obsolete. It has low overhead clearance, narrow width, rotting timber supports, and substandard approaches and guardrails. A new bridge is in the preliminary design stage (see following article).

"We are constantly evaluating the health of our bridges," said Rick Brater, manager of engineering services for the Roads Division. "These three bridges - Mt. Si, Elliott and South Park - showcase the diversity of our bridge inventory and the challenges we face.

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The King County Road Services Division will host a drop-in community meeting on Thursday, Dec. 2 to solicit public feedback on the conceptual design for a new Mt. Si Bridge across the middle fork of the Snoqualmie River.

After asking for public feedback on three types of truss bridge designs, the Roads Division has selected a Pratt truss structure for the new replacement bridge. It was picked for a combination of factors - cost, ease of construction, maintenance requirements, and aesthetics.

County engineers began the initial design work last month. Now, members of the community are invited to view conceptual bridge design plans and share feedback. The open house will be held Thursday, Dec. 2 from 7-9 p.m. at the Mt. Si High School commons, 8651 Meadowbrook Way SE, Snoqualmie.

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On Friday, Nov. 26, most Metro routes, including the streetcar, will operate on weekday schedules; however, some commuter routes and selected trips in the University District will be cancelled. The bus tunnel will be open, but Metro customer service offices will be closed.

For all the details on holiday transit service, visit Metro Online.

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Based on 177 comments received from riders and community groups during the comment period, the initial proposal was modified. In the final plan, six of the 35 existing bus stops along the first segment of Greenwood will be closed permanently and five will be relocated. Along the second segment, 11 of the 33 existing bus stops will be closed permanently.

For more details, visit the project page on Metro Online.

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Here is a list of King County Department of Transportation projects that may disrupt traffic and travel in the coming weeks:

Northeast 124th Street, north of Redmond - Work continues through the end of November on the Northeast 124th Street project between Willows Road and State Route 202. Most of the work now is concentrated at the bridge over the Sammamish River.

South 277th Street, between Auburn and Kent - Motorists may experience periodic traffic disruptions on South 277th Street between the West Valley Highway and 72nd Avenue South through October 2005 as a result of a major reconstruction project.

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